Samuel b



UNITED STATES PATENT OF IC SAMUEL B. BOULTON, OF LONDON, ENGLAND.

METHOD OF PRESERVING TIMBER.

SPECIFICATION forming part of Letters Patent No. 360.947, dated April 12, 1887.-

Application filed November 10, 1886. Serial No.218,480. (No specimens.) Patented in England December 12,1883, No. 5,723,- in France v January 4, 1884, No. 159,567, and in Belgium January 7, 1884, No. 63,776.

Toall whom it may concern;-

Be it known that I, SAMUEL BAGSTER BOUL- TON, a citizen of England, residing at Gannon street, in the city of London, England, have invented uew and useful Improvements in Treating Timber with Antiseptic or Preservative Fluids, (for which I have obtained a patent in Great Britain, dated December 12, 1883, No. 5,723; in France, dated January 4, 1884,- No. 159,567, and in Belgium, dated January 7,

1884, N 0. 63,776,) of which the following is a antiseptic properties, such as chloride or sulphate of zinc, sulphate of copper, corrosive sublimate, or mixtures of these with tar acids, such as carbolic, cresylic, and other acids, resulting from the treatment of the heavy oil of tar in the well-known manner,

or the distillates of the heavy oil of tar after a temperature of about 500 Fahrenheit has been reached; or I treat'the wood first with the one class of antiseptics, such as the metallic salts, and then with the tar acids; or I employ the basic substance now known as acridine, and other similar isomeric substances or other basic substances or alkaloids of the quinoline or leucoline series, or other basic substances of the heavier tar acids, such as may be obtained from the distillates coming over at high temperatures, and which are valuable antiseptics. Among the tar acids I prefer to employ those which are less volatile and less solublein water than carbolic acid and cresylic acid. Some of the above substances I have occasionally found to be contained in distillates obtained at a temperature below 500 Fahrenheit. For the purpose of effecting the impregnation of the wood with these several substances any known process may be used, and in some cases apparatus may be employed for the purpose similar to that described in my before-mentioned Patent No. 247 .602. After the wood has been so treated, and without subjecting the same to any drying process when the solutions employed are of an aqueous nature, [subject the timber to the process described in my said Patent No. 247.602. By thus first treating the wood with a class of substances that have highly antiseptic and preservative properties, and then with an oily or bituminous substance that may or may not have antiseptic properties, the first-named bOdies become effectually inclosed within the pores of the wood, while the heat with which the second class of bodies is supplied, combined with the exhaust employed, will effectually remove all watery particles, either originally contained in the wood or introduced by the aqueous solutions, such watery particles being replaced by the oily or bituminous substances, which will thus prevent the metallic salts or other substances first employed from being afterward dissolved out of the timber by the incursion of moisture from the soil or atmosphere, and will also impede the entrance into thewood of any further destructive agents.

I am aware that it has been proposed to inject timber, first, with metallic salts in a state of watery solution, and afterward with an oily or bituminous fluid, as described in Bethels British Provisional Specification No. 508 of 1853; but according to my improved process, instead of subjecting the timber after impregnation with a salt to a heating process in a drying-house to expel the moisture,which drying and heating process I consider to be detrimental to the timber, I expel such moisture by directly subjecting the impregnated timber to the action of the heated or bituminous body, according to the processes described in my specification to my United States patent above referred to.

In all cases my experience leads me to set the highest value for wood-preserving upon such antiseptics as are in themselves least volatile and least soluble in water, with an admixture of bodies which solidify within the pores of the timber. Tannin and other astringent bodies derived from vegetable substances may be used with good effect.

Having thus described the nature of my in vention and in what manner the same is to be performed, I claim 1. The process herein described of preserving wood, which consists in impregnating it with a solution of metallic salts and then expolling the moisture by directly subjecting the impregnated wood to the action of a heated bituminous body in a continuous partial vacuum in a closed vessel, substantially as set forth.

2. In a process of preserving wood, the series of steps which consists in first impregnating it with a metallic salt in solution with carbolic or cresylic acid, then expelling the moisture by directly subjecting the impregnated wood to a bath of hot bituminous fluid in a closed vessel wherein is maintained a continuous partial vacuum.

S. B. BOULTON.

Vitn esses Jim. 1?. M. DIILLARD, r Clerk to Abel (it linmy, Gonsulfing Engineers and Patent Agents, 28 Southampton Buildings, London, W. (1-

G. W. WESTLEY, l7 Gracechm'ch Street, London. 

